WO2021057923A1

WO2021057923A1 - Composite negative electrode material and preparation method therefor and lithium battery

Info

Publication number: WO2021057923A1
Application number: PCT/CN2020/117889
Authority: WO
Inventors: 庞春雷; 孔一鸣; 梁腾宇; 任建国; 贺雪琴
Original assignee: 贝特瑞新材料集团股份有限公司; 惠州市鼎元新能源科技有限公司
Priority date: 2019-09-26
Filing date: 2020-09-25
Publication date: 2021-04-01
Also published as: KR20210129691A; JP2022533857A; CN111162268B; EP3965192A1; US20220320505A1; CN111162268A; JP7317145B2; EP3965192A4

Abstract

The present application provides a composite negative electrode material and a preparation method therefor and a lithium battery. The composite negative electrode material comprises silicon-containing particles and a carbon coating layer, the carbon coating layer coating at least a part of the surface of the silicon-containing particles. In a Raman spectrum, the composite negative electrode material has a silicon characteristic peak A between 450 cm^-1 and 550 cm^-1, a carbon characteristic peak B between 1300 cm^-1 and 1400 cm^-1, a carbon characteristic peak C between 1530 cm^-1 and 1630 cm^-1, and a graphene structure characteristic peak D between 2500 cm^-1 and 2750 cm^-1. The preparation method comprises: in a protective atmosphere, introducing a reaction gas to react with silicon-containing particles, the reaction temperature being 700°C-1450°C, and the reaction gas comprising a carbon-containing gas, so that at least a part of the surface of the silicon-containing particles form a carbon coating layer, so as to obtain the composite negative electrode material. The composite negative electrode material has advantages such as a large cycle capacity retention ratio, good rate capability, and a small high-temperature aging loss.

Description

复合负极材料及其制备方法和锂离子电池Composite negative electrode material and preparation method thereof and lithium ion battery

本申请要求于2019年9月26日提交中国专利局，申请号为2019109183208、发明名称为“一种复合负极材料及其制备方法和锂离子电池”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。This application claims the priority of a Chinese patent application filed with the Chinese Patent Office on September 26, 2019. The application number is 2019109183208 and the invention title is "a composite anode material and its preparation method and lithium ion battery". The entire content of the application is approved. The reference is incorporated in this application.

技术领域Technical field

本申请属于电池材料技术领域，涉及一种负极材料及其制备方法和锂离子电池，尤其涉及一种复合负极材料及其制备方法和锂离子电池。This application belongs to the technical field of battery materials, and relates to a negative electrode material and a preparation method thereof and a lithium ion battery, and in particular to a composite negative electrode material and a preparation method thereof, and a lithium ion battery.

背景技术Background technique

锂离子电池是一种二次电池(充电电池)，它主要依靠锂离子在正极和负极之间移动来工作。在充放电过程中，Li ⁺在两个电极之间往返嵌入和脱嵌：充电时，Li ⁺从正极脱嵌，经过电解质嵌入负极，负极处于富锂状态；放电时则相反。 Lithium ion battery is a kind of secondary battery (rechargeable battery), which mainly relies on the movement of lithium ions between the positive and negative electrodes to work. During the charging and discharging process, Li ⁺ intercalates and deintercalates back and forth between the two electrodes: when charging, Li ^{+ is} deintercalated from the positive electrode and inserted into the negative electrode through the electrolyte, and the negative electrode is in a lithium-rich state; the opposite is true during discharge.

锂离子电池的负极是由负极活性物质碳材料或非碳材料、粘合剂和添加剂混合制成糊状胶合剂均匀涂抹在铜箔两侧，经干燥、辊压而成。锂离子电池能否成功地制成，关键在于能否制备出可逆地脱/嵌锂离子的负极材料。一般来说，选择一种好的负极材料应遵循以下原则：比能量高；相对锂电极的电极电位低；充放电反应可逆性好；与电解液和粘结剂的兼容性好；比表面积小(<10m ²/g)，真密度高(>2.0g/cm ³)；嵌锂过程中尺寸和机械稳定性好；资源丰富，价格低廉；在空气中稳定、无毒副作用。目前，已实际用于锂离子电池的负极材料一般都是碳素材料，如石墨、软碳(如焦炭等)、硬碳等。正在探索的负极材料有氮化物、PAS、锡基氧化物、锡合金、纳米负极材料，以及其他的一些金属间化合物等。 The negative electrode of a lithium ion battery is made by mixing the negative active material carbon material or non-carbon material, binder and additives to form a paste glue that is uniformly applied to both sides of the copper foil, dried and rolled. The key to the successful manufacture of lithium-ion batteries lies in the preparation of negative electrode materials that can reversibly de-intercalate lithium ions. Generally speaking, choosing a good negative electrode material should follow the following principles: high specific energy; low electrode potential relative to lithium electrode; good reversibility of charge and discharge reaction; good compatibility with electrolyte and binder; small specific surface area (<10m ² /g), high true density (>2.0g/cm ³ ); good size and mechanical stability during lithium insertion; abundant resources and low price; stable in the air without toxic side effects. At present, the negative electrode materials that have been actually used in lithium-ion batteries are generally carbon materials, such as graphite, soft carbon (such as coke, etc.), hard carbon, and so on. The anode materials being explored include nitrides, PAS, tin-based oxides, tin alloys, nano-anode materials, and other intermetallic compounds.

近年来，对高性能锂离子电池的需求日益迫切，以电子消费品、电动汽车等为代表的产品市场不断扩大，对高性能锂离子电池负极材料的需要也越来越迫切。In recent years, the demand for high-performance lithium-ion batteries has become increasingly urgent. The market for products represented by consumer electronics and electric vehicles has continued to expand, and the need for high-performance lithium-ion battery anode materials has become more and more urgent.

一种锂离子电池复合负极材料镀膜的改性方法，该方案中，复合负极材料包括负极材料及其表面包覆的金属膜、金属氧化膜，包覆的金属膜或金属氧化膜采用磁控溅射镀膜法制备。A method for modifying the coating of composite negative electrode materials for lithium-ion batteries. In the scheme, the composite negative electrode material includes the negative electrode material and the metal film and metal oxide film coated on the surface thereof, and the coated metal film or metal oxide film adopts magnetron sputtering Prepared by shot coating method.

另一种改性硅基负极材料及其制备方法与应用，该方案中，改性硅基负极材料包括硅基负极基材，在所述硅基负极基材中还嵌有锂离子。其制备方法包括配制含锂的芳烃化合物溶液的步骤和对硅基负极基材进行嵌锂处理的步骤。Another modified silicon-based negative electrode material and a preparation method and application thereof. In this solution, the modified silicon-based negative electrode material includes a silicon-based negative electrode substrate in which lithium ions are also embedded. The preparation method includes the steps of preparing a lithium-containing aromatic compound solution and the steps of performing lithium intercalation treatment on the silicon-based negative electrode substrate.

又一种锂离子电池氧化亚硅复合负极材料、制备方法及其用途。所述氧化亚硅复合材料由氧化亚硅粉末和均匀致密涂覆在氧化亚硅粉末表面的导电碳层组成。Another silicon oxide composite negative electrode material for a lithium ion battery, a preparation method and application thereof. The silicon oxide composite material is composed of silicon oxide powder and a conductive carbon layer uniformly and densely coated on the surface of the silicon oxide powder.

然而上述方案均存在着负极材料的循环性能和倍率性能有待提高的问题。However, the above solutions all have the problem that the cycle performance and rate performance of the negative electrode material need to be improved.

申请内容Application content

基于此，本申请的目的在于提供一种复合负极材料及其制备方法和锂离子电池。本申请提供的复合负极材料具有循环容量保持率高、倍率性能好、高温老化损失小等优点。Based on this, the purpose of the present application is to provide a composite negative electrode material, a preparation method thereof, and a lithium ion battery. The composite negative electrode material provided by the present application has the advantages of high cycle capacity retention, good rate performance, and low high-temperature aging loss.

为达此目的，本申请采用以下技术方案：To achieve this goal, this application adopts the following technical solutions:

第一方面，本申请提供一种复合负极材料，所述复合负极材料包括含硅颗粒和碳包覆层，所述碳包覆层包覆所述含硅颗粒的至少部分表面；In a first aspect, the present application provides a composite negative electrode material, the composite negative electrode material includes silicon-containing particles and a carbon coating layer, and the carbon coating layer covers at least part of the surface of the silicon-containing particles;

在拉曼光谱中，所述复合负极材料在450cm ^-1～550cm ^-1间具有硅特征峰A，在1300cm ^-1～1400cm ^-1间具有碳特征峰B，在1530cm ^-1～1630cm ^-1间有碳特征峰C，在2500cm ^-1～2750cm ^-1间具有石墨烯结构特征峰D。 In the Raman spectroscopy, the composite negative electrode material has a characteristic silicon peak A between ^{450 cm -1} and 550 cm ^-1 ^{, a characteristic carbon peak B between 1300 cm -1} and 1400 ^{cm -1,} and a characteristic peak B between 1530 cm ^-1 and 1630 cm ^-1 There is a characteristic peak C of carbon, and a characteristic peak D of the graphene structure between ^{2500 cm -1} and 2750 cm ^-1.

本申请提供的复合负极材料的拉曼光谱峰中具有石墨烯结构特征峰D，说明其碳包覆层中含有少量石墨烯结构，含石墨烯结构的碳包覆层可提高产品电导率、提高倍率性能，均匀生长的上述石墨烯结构能够进一步提升产品颗粒表面与电解液的固液界面稳定，形成均一的SEI膜，提高产品的高温保存性能，降低高温老化损失。The Raman spectrum peak of the composite negative electrode material provided in the present application has the characteristic peak D of the graphene structure, indicating that the carbon coating layer contains a small amount of graphene structure, and the carbon coating layer containing the graphene structure can improve the electrical conductivity of the product. The rate performance and the uniformly grown graphene structure can further improve the stability of the solid-liquid interface between the surface of the product particles and the electrolyte, form a uniform SEI film, improve the high-temperature storage performance of the product, and reduce the high-temperature aging loss.

在一种可行的实施方式中，在拉曼光谱中，所述硅特征峰A的峰强度I _A与所述石墨烯结构特征峰D的峰强度I _D的比值I _A/I _D大于0.1且小于30，且所述石墨烯结构特征峰D的峰强度I _D与所述碳特征峰B的峰强度I _B的比值I _D/I _B大于0且小于1。 In one possible embodiment, in the Raman spectrum, wherein the silicon peak intensity I _A of the peak A to the peak D graphene structure characteristic peak intensity ratio I _A I _D / I _D is greater than 0.1 and It is less than 30, and the ratio I _D /I _B _{of the peak intensity I D} _{of the characteristic peak D of the graphene structure to the peak intensity I B} of the characteristic carbon peak B is greater than 0 and less than 1.

在一种可行的实施方式中，所述复合负极材料满足以下条件a～f的至少一者：In a feasible embodiment, the composite negative electrode material satisfies at least one of the following conditions a to f:

a.所述含硅颗粒包括Si、SiO _x和硅酸盐中的至少一种，其中，0<x<2； a. The silicon-containing particles include _{at least one of Si, SiO x} and silicate, wherein 0<x<2;

b.所述含硅颗粒的平均粒径为0.1um～20um；b. The average particle size of the silicon-containing particles is 0.1um to 20um;

c.所述含硅颗粒的比表面积大于150cm ²/g； c. The specific surface area of the silicon-containing particles is greater than 150 cm ² /g;

d.所述碳包覆层为无机碳材料层；d. The carbon coating layer is an inorganic carbon material layer;

e.所述碳包覆层的厚度为10nm～300nm；e. The thickness of the carbon coating layer is 10 nm to 300 nm;

f.在所述复合负极材料中，所述碳包覆层的质量分数为1％～65％。f. In the composite negative electrode material, the mass fraction of the carbon coating layer is 1% to 65%.

第二方面，本申请提供一种复合负极材料的制备方法，所述方法包括以下步骤：In a second aspect, this application provides a method for preparing a composite negative electrode material. The method includes the following steps:

在保护性气氛下，通入反应气体与含硅颗粒进行反应，反应温度为700℃～1450℃，所述反应气体包括含碳气体，使得所述含硅颗粒的至少部分表面形成碳包覆层，得到所述复合负极材料。In a protective atmosphere, a reaction gas is introduced to react with silicon-containing particles, and the reaction temperature is 700°C to 1450°C. The reaction gas includes a carbon-containing gas, so that at least part of the surface of the silicon-containing particles forms a carbon coating layer , To obtain the composite negative electrode material.

本申请提供的复合负极材料的制备方法，将含硅颗粒材料加热至预设温度后，通过含碳气体，使得含碳气体在含硅颗粒表面进行反应，含有石墨烯结构的碳包覆层原位生长在含硅颗粒的至少部分表面，含石墨烯结构的碳包覆层可提高产品电导率、提高倍率性能；而非直接使用石墨烯进行包覆，大幅降低了制备难度。整个制备过程操作简单，流程短，工艺成熟，生产难度低，成本可控，有利于在工业化大生产中进行应用。In the preparation method of the composite negative electrode material provided in the present application, the silicon-containing particulate material is heated to a preset temperature, and then the carbon-containing gas is used to react on the surface of the silicon-containing particles. The site grows on at least part of the surface of the silicon-containing particles, and the carbon coating layer containing the graphene structure can increase the conductivity of the product and increase the rate performance; instead of directly using graphene for coating, it greatly reduces the difficulty of preparation. The entire preparation process has simple operation, short flow, mature technology, low production difficulty, and controllable cost, which is conducive to application in large-scale industrial production.

在一种可行的实施方式中，所述方法满足以下条件a～f的至少一者：In a feasible implementation manner, the method satisfies at least one of the following conditions a to f:

在一种可行的实施方式中，在拉曼光谱中，所述复合负极材料在450cm ^-1～550cm ^-1间具有硅特征峰A，在1300cm ^-1～1400cm ^-1间具有碳特征峰B，在1530cm ^-1～1630cm ^-1间有碳特征峰C，在2500cm ^-1～2750cm ^-1间具有石墨烯结构特征峰D；所述硅特征峰A的峰强度I _A与所述石墨烯结构特征峰D的峰强度I _D的比值I _A/I _D大于0.1且小于30，且所述石墨烯结构特征峰D的峰强度I _D与所述碳特征峰B的峰强度I _B的比值I _D/I _B大于0且小于1。 In one possible embodiment, in the Raman spectrum, the composite material between the anode A having characteristic peaks in the silicon 450cm ^{^-1} ~ 550cm ^-1, between B having characteristic peaks in carbon 1300cm ^{^-1} ~ 1400cm ^-1, There is a carbon characteristic peak C between 1530 cm ^-1 ～1630 cm ^-1 and a graphene structure characteristic peak D between ^{2500 cm -1} and 2750 cm ^-1 _{; the peak intensity I A of} the silicon characteristic peak A and the graphene structure characteristic peak intensity I _D of the D peak ratio I _a / I _D is greater than 0.1 and less than 30, and the peak intensity I _D D graphene structure characteristic peaks and peak intensity of the carbon peaks of the B I _B I _D ratio /I _{B is} greater than 0 and less than 1.

在一种可行的实施方式中，所述方法满足以下条件a～b的至少一者：In a feasible implementation manner, the method satisfies at least one of the following conditions a to b:

a.所述保护性气氛包括氮气、氦气、氖气、氩气、氪气和氙气中的至少一种；a. The protective atmosphere includes at least one of nitrogen, helium, neon, argon, krypton and xenon;

b.所述含碳气体包括甲烷、乙炔、乙烯、丙炔、丙烯、甲苯蒸气、苯蒸气、丙酮蒸气和甲醛蒸气中的至少一种。b. The carbon-containing gas includes at least one of methane, acetylene, ethylene, propyne, propylene, toluene vapor, benzene vapor, acetone vapor, and formaldehyde vapor.

在一种可行的实施方式中，所述反应气体还包括辅助气体，所述辅助气体包括氢气。In a feasible embodiment, the reaction gas further includes an auxiliary gas, and the auxiliary gas includes hydrogen.

在一种可行的实施方式中，所述含碳气体和所述辅助气体的摩尔比为(2～10)：1。In a feasible embodiment, the molar ratio of the carbon-containing gas to the auxiliary gas is (2-10):1.

在一种可行的实施方式中，所述方法满足以下条件a～d的至少一者：In a feasible implementation manner, the method satisfies at least one of the following conditions a to d:

a.所述反应的方式为化学气相沉积；a. The method of the reaction is chemical vapor deposition;

b.所述反应的方式为化学气相沉积，所述化学气相沉积的反应温度为700℃～1150℃；b. The method of the reaction is chemical vapor deposition, and the reaction temperature of the chemical vapor deposition is 700°C to 1150°C;

c.所述反应的方式为化学气相沉积，所述化学气相沉积的保温时间为3h～16h；c. The method of the reaction is chemical vapor deposition, and the holding time of the chemical vapor deposition is 3h-16h;

d.所述反应的方式为化学气相沉积，所述化学气相沉积的反应气压为1.0atm～10.0atm。d. The method of the reaction is chemical vapor deposition, and the reaction pressure of the chemical vapor deposition is 1.0 atm to 10.0 atm.

在一种可行的实施方式中，所述方法包括以下步骤：In a feasible implementation, the method includes the following steps:

在保护性气氛下，将含硅颗粒加热至700℃～1450℃；In a protective atmosphere, heat the silicon-containing particles to 700°C to 1450°C;

通入反应气体进行化学气相沉积，所述反应气体包括含碳气体，使得含硅颗粒的至少部分表面形成碳包覆层，得到复合负极材料。The chemical vapor deposition is carried out by introducing a reaction gas, the reaction gas including a carbon-containing gas, so that at least part of the surface of the silicon-containing particles forms a carbon coating layer to obtain a composite negative electrode material.

在保护性气氛下，将含硅颗粒加热至700℃～1150℃；In a protective atmosphere, heat the silicon-containing particles to 700°C to 1150°C;

将含碳气体与氢气按照摩尔比为(2～10)：1通入所述含硅颗粒中进行化学气相沉积反应，控制反应气压1.0atm～10.0atm，保温3h～16h，使得所述含硅颗粒的至少部分表面形成碳包覆层，得到所述复合负极材料。The carbon-containing gas and hydrogen are introduced into the silicon-containing particles at a molar ratio of (2-10):1 to perform chemical vapor deposition reaction, the reaction pressure is controlled to be 1.0atm-10.0atm, and the temperature is maintained for 3h-16h, so that the silicon-containing A carbon coating layer is formed on at least part of the surface of the particles to obtain the composite negative electrode material.

第三方面，本申请提供一种锂离子电池，所述锂离子电池包含如上述第一方面的复合负极材料或根据上述第二方面的制备方法制得的复合负极材料。In a third aspect, the present application provides a lithium ion battery, the lithium ion battery comprising the composite negative electrode material of the first aspect described above or the composite negative electrode material prepared according to the preparation method of the second aspect described above.

与现有技术相比，本申请具有以下有益效果：Compared with the prior art, this application has the following beneficial effects:

(1)本申请提供的复合负极材料具有独特的拉曼光谱峰具有石墨烯结构特征峰D，说明其碳包覆层中含有少量石墨烯结构，含石墨烯结构的碳包覆层可提高产品电导率、提高倍率性能，均匀生长的上述石墨烯结构能够进一步提升产品颗粒表面与电解液的固液界面稳定，形成均一的SEI膜，提高产品的高温保存性能，该复合负极材料具有循环容量保持率高、倍率性能好、高温老化损失小等优点。(1) The composite anode material provided by this application has unique Raman spectral peaks and graphene structure characteristic peak D, indicating that the carbon coating layer contains a small amount of graphene structure, and the carbon coating layer containing the graphene structure can improve the product Conductivity, increase rate performance, and the uniformly grown graphene structure can further improve the stability of the solid-liquid interface between the particle surface of the product and the electrolyte, form a uniform SEI film, and improve the high-temperature storage performance of the product. The composite anode material has a cycle capacity retention High rate, good rate performance, low temperature aging loss and other advantages.

(2)本申请提供的制备方法，将含硅颗粒材料加热至预设温度后，通过含碳气体，使得含碳气体在含硅颗粒表面进行化学气相沉积，原位生成碳包覆层，并且碳包覆层中含有少量石墨烯，而非直接使用石墨烯进行包覆，大幅降低了制备难度。整个制备过程操作简单，流程短，工艺成熟，生产难度低，成本可控，有利于在工业化大生产中进行应用。(2) In the preparation method provided by the present application, after heating the silicon-containing particulate material to a preset temperature, the carbon-containing gas is subjected to chemical vapor deposition on the surface of the silicon-containing particles by using a carbon-containing gas to form a carbon coating layer in situ, and The carbon coating layer contains a small amount of graphene instead of directly using graphene for coating, which greatly reduces the difficulty of preparation. The entire preparation process has simple operation, short flow, mature technology, low production difficulty, and controllable cost, which is conducive to application in large-scale industrial production.

附图说明Description of the drawings

图1为本申请提供的复合负极材料的制备方法的工艺流程图；Fig. 1 is a process flow diagram of a method for preparing a composite negative electrode material provided by this application;

图2为实施例1制备的复合负极材料的拉曼光谱；2 is a Raman spectrum of the composite anode material prepared in Example 1;

图3为实施例1制备的复合负极材料的循环性能曲线；Figure 3 is a cycle performance curve of the composite negative electrode material prepared in Example 1;

图4为实施例2制备的复合负极材料的拉曼光谱；4 is a Raman spectrum of the composite anode material prepared in Example 2;

图5为实施例2制备的复合负极材料的循环性能曲线；Figure 5 is a cycle performance curve of the composite negative electrode material prepared in Example 2;

图6为对比例1制备的复合负极材料的拉曼光谱；Figure 6 is a Raman spectrum of the composite negative electrode material prepared in Comparative Example 1;

图7为对比例1制备的复合负极材料的循环性能曲线。FIG. 7 is a cycle performance curve of the composite negative electrode material prepared in Comparative Example 1. FIG.

具体实施方式detailed description

为更好地说明本申请，便于理解本申请的技术方案，下面对本申请进一步详细说明。但下述的实施例仅仅是本申请的简易例子，并不代表或限制本申请的权利保护范围，本申请保护范围以权利要求书为准。In order to better explain the application and facilitate the understanding of the technical solutions of the application, the application will be further described in detail below. However, the following embodiments are only simple examples of this application, and do not represent or limit the scope of protection of the rights of this application. The scope of protection of this application is subject to the claims.

以下为本申请典型但非限制性实施例：The following are typical but non-limiting examples of the application:

第一方面，本申请实施例提供一种复合负极材料，所述复合负极材料包括所述复合负极材料包括含硅颗粒和碳包覆层，所述碳包覆层包覆所述含硅颗粒的至少部分表面。在拉曼光谱中，所述复合负极材料在450～550cm ^-1间具有硅特征峰A，在1300～1400cm ^-1间具有碳特征峰B，在1530～1630cm ^-1间有碳特征峰C，在2500～2750cm ^-1间具有石墨烯结构特征峰D。 In a first aspect, an embodiment of the present application provides a composite negative electrode material. The composite negative electrode material includes silicon-containing particles and a carbon coating layer. The carbon coating layer covers the silicon-containing particles. At least part of the surface. In the Raman spectrum, the composite negative electrode material having between 450 ~ 550cm ^-1 silicon characteristic peaks A, Room B having characteristic peaks in carbon 1300 ~ 1400cm ^-1, at 1530 ~ 1630cm ^-1 among carbon peaks characteristic C, There is a characteristic peak D of graphene structure between 2500 and 2750 cm ^-1.

本申请提供的复合负极材料的拉曼光谱中，特征峰A为硅特征峰，特征峰B和特征峰C为碳特征峰，特征峰D为石墨烯结构特征峰。上述含有石墨烯结构的碳包覆层原位生长在含硅颗粒的至少部分表面，含石墨烯结构的碳包覆层可提高产品电导率、提高倍率性能，均匀生长的上述石墨烯结构能够进一步提升产品颗粒表面与电解液的固液界面稳定，形成均一的SEI膜，提高产品的高温保存性能，降低高温老化损失。In the Raman spectrum of the composite negative electrode material provided in the present application, characteristic peak A is a characteristic peak of silicon, characteristic peak B and characteristic peak C are characteristic peaks of carbon, and characteristic peak D is a characteristic peak of graphene structure. The carbon coating layer containing the graphene structure is grown in situ on at least part of the surface of the silicon-containing particles. The carbon coating layer containing the graphene structure can increase the electrical conductivity of the product and increase the rate performance. The uniformly grown graphene structure can further Improve the stability of the solid-liquid interface between the particle surface of the product and the electrolyte to form a uniform SEI film, improve the high-temperature storage performance of the product, and reduce the high-temperature aging loss.

本申请提供的这种具有特殊拉曼光谱特征的复合负极材料具有循环容量保持率高、倍率性能好、高温老化损失小等优点。The composite negative electrode material with special Raman spectrum characteristics provided in this application has the advantages of high cycle capacity retention, good rate performance, and low high-temperature aging loss.

以下作为本申请可选的技术方案，但不作为对本申请提供的技术方案的限制，通过以下优选的技术方案，可以更好的达到和实现本申请的技术目的和有益效果。The following are optional technical solutions of this application, but not as a limitation to the technical solutions provided in this application. Through the following preferred technical solutions, the technical objectives and beneficial effects of this application can be better achieved and realized.

作为本申请可选的技术方案，在拉曼光谱中，所述硅特征峰A的峰强度I _A与所述石墨烯结构特征峰D的峰强度I _D的比值I _A/I _D大于0.1且小于30，例如I _A/I _D为0.2、0.5、1、5、10、15、20、25或29等，且所述石墨烯结构特征峰D的峰强度I _D与所述碳特征峰B的峰强度I _B的比值I _D/I _B大于0且小于1，例如I _D/I _B为0.1、0.2、0.32、 0.4、0.5、0.6、0.7、0.8或0.9等。 As an alternative aspect of the present application, in the Raman spectrum, wherein the silicon peak intensity I _A of the peak A to the peak D graphene structure characteristic peak intensity ratio I _A I _D / I _D is greater than 0.1 and less than 30, for example, I _a / I _D is 0.2,0.5,1,5,10,15,20,25 or the like 29, and the peak intensity I _D D graphene structure characteristic peak and characteristic peak of the carbon B The ratio I _D /I _B of the peak intensity I _B is greater than 0 and less than 1, for example, I _D /I _B is 0.1, 0.2, 0.32, 0.4, 0.5, 0.6, 0.7, 0.8, or 0.9.

在本申请中，特征峰A为硅特征峰，特征峰D为石墨烯结构特征峰，故I _A/I _D可表示石墨烯结构生长的均匀性，该值越小，石墨烯结构生长越均匀，但若该值低于0.1，说明碳包覆层厚度过大，反而会影响锂离子的传输，导致性能劣化，故本申请通过控制0.1<I _A/I _D<30，实现了产品石墨烯结构生长均匀且碳包覆层厚度适宜，得到了较好的产品性能。特征峰B和特征峰C为碳材料特征峰，特征峰D为石墨烯结构特征峰，特征峰B可表示碳材料中无定形或片层边缘的缺陷结构，故I _D/I _B可用于表征产品中石墨烯结构与缺陷结构的比例，I _D/I _B<1说明本申请的复合负极材料是利用原位生长得到的，碳包覆层中含有大量细密石墨烯结构，而非直接使用石墨烯片对含硅颗粒进行包覆，大幅降低了制备难度，具备生产性强、成本可控的优点。 In the present application, wherein A is silicon peak characteristic peaks, peak D is a characteristic peaks graphene structure, so I _A / I _D may represent the uniformity of the growth of graphene structure, the smaller the value, the more uniform the growth of graphene structure , But if the value is less than 0.1, it means that the thickness of the carbon coating layer is too large, which will affect the transmission of lithium ions and cause performance degradation. Therefore, this application realizes the product graphene _{by controlling 0.1<I A} /I _{D <30} The structure grows uniformly and the thickness of the carbon coating layer is appropriate, resulting in better product performance. Characteristic peaks B and peaks C is a carbon material characteristic peaks, characteristic peaks D graphene structure characteristic peaks, characteristic peaks B may represent a carbon material is amorphous or defect structure sheet edge, so the I _D / I _B may be used to characterize The ratio of the graphene structure to the defect structure in the product, I _D /I _B <1 indicates that the composite anode material of this application is obtained by in-situ growth, and the carbon coating layer contains a large amount of fine graphene structure instead of directly using graphite The olefin sheet coats the silicon-containing particles, which greatly reduces the difficulty of preparation and has the advantages of high productivity and controllable cost.

作为本申请可选的技术方案，所述碳包覆层为无机碳材料层。As an optional technical solution of the present application, the carbon coating layer is an inorganic carbon material layer.

需要说明的是，碳包覆层包覆在含硅颗粒的表面，本申请中所指的表面不仅仅是颗粒的平整表面，碳包覆层还可以填充于颗粒表面的裂缝、孔道等结构内，在此不做限定。It should be noted that the carbon coating layer covers the surface of the silicon-containing particles. The surface referred to in this application is not only the flat surface of the particles. The carbon coating layer can also be filled in the cracks, pores and other structures on the surface of the particles. , It is not limited here.

在其中一些实施例中，在所述复合负极材料中，碳包覆层的质量分数为1％～65％，例如1％、10％、20％、30％、40％、50％、60％或65％等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。本申请中，碳包覆层的质量分数低于1％会导致包覆量不足，无法充分发挥该产品性能，碳包覆层的质量分数高于65％会导致碳包覆量过高，影响容量的同时阻碍锂离子传输，降低负极材料的综合性能。In some of the embodiments, in the composite negative electrode material, the mass fraction of the carbon coating layer is 1%-65%, for example, 1%, 10%, 20%, 30%, 40%, 50%, 60% Or 65%, etc., but not limited to the listed values, and other unlisted values within this range of values are also applicable. In this application, if the mass fraction of the carbon coating layer is less than 1%, the coating amount will be insufficient, and the product performance cannot be fully utilized. The mass fraction of the carbon coating layer higher than 65% will cause the carbon coating amount to be too high and affect At the same time, the capacity hinders the transmission of lithium ions and reduces the overall performance of the negative electrode material.

在其中一些实施例中，在所述复合负极材料中，所述碳包覆层的厚度为10nm～300nm，例如可以是10nm、20nm、50nm、80nm、100nm、150nm、200nm、250nm或300nm等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。碳包覆层过厚，锂离子传输效率降低，不利于材料大倍率充放电，降低负极材料的综合性能，碳包覆层过薄，不利于增加负极材料的导电性且对材料的体积膨胀抑制性能较弱，导致长循环性能价差。In some of the embodiments, in the composite negative electrode material, the thickness of the carbon coating layer is 10 nm to 300 nm, for example, it may be 10 nm, 20 nm, 50 nm, 80 nm, 100 nm, 150 nm, 200 nm, 250 nm, or 300 nm, etc., However, it is not limited to the listed values, and other unlisted values within this range of values are also applicable. If the carbon coating layer is too thick, the lithium ion transmission efficiency is reduced, which is not conducive to the large-rate charge and discharge of the material, and the overall performance of the negative electrode material is reduced. The carbon coating layer is too thin, which is not conducive to increasing the conductivity of the negative electrode material and suppressing the volume expansion of the material The performance is weak, resulting in a long-cycle performance price difference.

作为本申请可选的技术方案，所述含硅颗粒包括Si、SiO _x和硅酸盐中的至少一种，其中，0<x<2。本申请中所述含硅颗粒不限定特定的空间结构、粒度、形貌、掺杂、硅碳复合等，不同的含硅颗粒仅需微调制备具体参数即可得到本申请提出的复合负极材料。 As an optional technical solution of the present application, the silicon-containing particles include _{at least one of Si, SiO x} and silicate, where 0<x<2. The silicon-containing particles in this application do not limit the specific spatial structure, particle size, morphology, doping, silicon-carbon composite, etc., and different silicon-containing particles only need to fine-tune the specific preparation parameters to obtain the composite anode material proposed in this application.

在其中一些实施例中，所述含硅颗粒的平均粒径为0.1um～20um，例如可以是0.1um、0.5um、1um、3um、5um、10um、13um、15um、18um、20um等。含硅颗粒的平均粒径控制在上述范围内，有利于负极材料循环性能的提升。In some embodiments, the average particle size of the silicon-containing particles is 0.1um-20um, for example, it can be 0.1um, 0.5um, 1um, 3um, 5um, 10um, 13um, 15um, 18um, 20um, etc. The average particle size of the silicon-containing particles is controlled within the above range, which is beneficial to the improvement of the cycle performance of the negative electrode material.

在其中一些实施例中，所述含硅颗粒的比表面积大于150cm ²/g，例如可以是150cm ²/g、180cm ²/g、200cm ²/g、250cm ²/g、300cm ²/g、400cm ²/g或500cm ²/g等。所述含硅颗粒的比表面积在上述范围内，有利于提高由该负极材料制成的锂电池的首次效率，有利于提高负极材料的循环性能。 In some of these embodiments, the silicon-containing particles of surface area greater than 150cm ² / g, for example, be ^{^{150cm 2 / g, 180cm 2 /}} g, 200cm 2 / g, 250cm 2 / g, 300cm 2 / g, 400cm ² /g or 500cm ² /g, etc. The specific surface area of the silicon-containing particles within the above range is beneficial to improve the primary efficiency of the lithium battery made of the negative electrode material, and is beneficial to improve the cycle performance of the negative electrode material.

在其中一些实施例中，所述SiO _x中0<x<2，例如x为0.1、0.2、0.5、0.8、1、1.2、1.5、1.7或1.9等。 In some of the embodiments _{, 0<x<2 in the SiO x} , for example, x is 0.1, 0.2, 0.5, 0.8, 1, 1.2, 1.5, 1.7, or 1.9.

第二方面，本申请提供一种复合负极材料的制备方法，所述方法包括以下步骤：In the second aspect, the present application provides a method for preparing a composite negative electrode material, the method includes the following steps:

本申请提供的方法将含碳气体与含硅颗粒在700℃～1450℃下进行反应，碳原位生长在含硅颗粒的至少部分表面，形成碳包覆层，该碳包覆层具有石墨烯结构，可提高产品电导率、提高倍率性能，均匀生长的石墨烯结构能够进一步提升产品颗粒表面与电解液的固液界面稳定，形成均一的SEI膜，提高产品的高温保存性能，降低高温老化损失。The method provided in the present application reacts carbon-containing gas with silicon-containing particles at 700°C to 1450°C, and carbon is grown in situ on at least part of the surface of the silicon-containing particles to form a carbon coating layer. The carbon coating layer has graphene. The structure can improve the conductivity of the product and the rate performance. The uniformly grown graphene structure can further improve the stability of the solid-liquid interface between the surface of the product particles and the electrolyte, forming a uniform SEI film, improving the high-temperature storage performance of the product, and reducing the high-temperature aging loss .

本申请提供的制备方法中，反应气体与含硅颗粒材料进行的是化学气相沉积反应，本申请提供的制备方法通过简单的化学气相沉积即可制备得到本申请所述复合负极材料。In the preparation method provided in this application, the reaction gas and the silicon-containing particulate material undergo a chemical vapor deposition reaction. The preparation method provided in this application can be prepared by simple chemical vapor deposition to obtain the composite negative electrode material described in this application.

制得的所述复合负极材料，在拉曼光谱中，所述复合负极材料在450～550cm ^-1间具有硅特征峰A，在1300～1400cm ^-1间具有碳特征峰B，在1530～1630cm ^-1间有碳特征峰C，在2500～2750cm ^-1间具有石墨烯结构特征峰D。优选地，所述硅特征峰A的峰强度I _A与所述石墨烯结构特征峰D的峰强度I _D的比值I _A/I _D大于0.1且小于30，且所述石墨烯结构特征峰D的峰强度I _D与所述碳特征峰B的峰强度I _B的比值I _D/I _B大于0且小于1。 In the prepared composite negative electrode material, in the Raman spectrum, the composite negative electrode material has a characteristic silicon peak A between ^{450 and 550 cm -1} , a characteristic carbon peak B between 1300 and 1400 cm -1, and a characteristic peak B between 1530 and 1630 cm ^-1 carbon peaks between ^-1 C, at between 2500 ~ 2750cm ^-1 characteristic peak having a graphene structure D. Preferably, the peak intensity I _D of the silicon peak intensity I _A characteristic peak A to the peak D graphene structure wherein a ratio I _A / I _D is greater than 0.1 and less than 30, and the graphene structure characteristic peak D The ratio I _D /I _B of the peak intensity I _D of the carbon characteristic peak B to the peak intensity I _B of the carbon characteristic peak B is greater than 0 and less than 1.

作为本申请可选的技术方案，所述保护性气氛包括氮气、氦气、氖气、氩气、氪气和氙气中的至少一种。As an optional technical solution of the present application, the protective atmosphere includes at least one of nitrogen, helium, neon, argon, krypton, and xenon.

在其中一些实施例中，所述含碳气体包括甲烷、乙炔、乙烯、丙炔、丙烯、甲苯蒸气、苯蒸气、丙酮蒸气和甲醛蒸气中的至少一种。In some embodiments, the carbon-containing gas includes at least one of methane, acetylene, ethylene, propyne, propylene, toluene vapor, benzene vapor, acetone vapor, and formaldehyde vapor.

在其中一些实施例中，所述反应气体中还包括辅助气体。In some of the embodiments, the reaction gas further includes auxiliary gas.

在其中一些实施例中，所述辅助气体包括氢气。氢气可以控制某些含碳气体(例如乙炔)的反应速度，使其更容易在大流量下产生石墨烯结构，以提高生产效率。In some of the embodiments, the auxiliary gas includes hydrogen. Hydrogen can control the reaction rate of certain carbon-containing gases (such as acetylene), making it easier to produce graphene structures at large flow rates, so as to improve production efficiency.

在其中一些实施例中，所述含碳气体和辅助气体的摩尔比为(2～10):1，例如 2:1、3:1、4:1、5:1、6:1、7:1、8:1、9:1或10:1等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。In some of the embodiments, the molar ratio of the carbon-containing gas and the auxiliary gas is (2-10):1, such as 2:1, 3:1, 4:1, 5:1, 6:1, 7: 1, 8:1, 9:1 or 10:1, etc., but not limited to the listed values, other unlisted values within this range of values are also applicable.

作为本申请可选的技术方案，所述反应气体的通入速度为0.1～6.0L/min，例如0.1L/min、0.3L/min、0.5L/min、1.0L/min、2.0L/min、3.0L/min、4.0L/min、5.0L/min或6.0L/min等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。本申请中，如果反应气体的通入速度过快，会导致石墨烯结构无法生成；如果反应气体的通入速度过慢，会导致沉积效率过低，影响生产性和实用价值。但是该优选条件是以5L容积的小型实验炉进行实验得到的，对于其他容积与之相差太大的反应器可能并不适用。因此，本申请并不限定反应气体的通入速度为上述优选范围，可根据制备条件适应性地调整。As an optional technical solution of the present application, the feed rate of the reaction gas is 0.1 to 6.0 L/min, for example, 0.1 L/min, 0.3 L/min, 0.5 L/min, 1.0 L/min, 2.0 L/min , 3.0L/min, 4.0L/min, 5.0L/min or 6.0L/min, etc., but not limited to the listed values, other unlisted values within this range of values are also applicable. In this application, if the feed rate of the reactive gas is too fast, the graphene structure will not be generated; if the feed rate of the reactive gas is too slow, the deposition efficiency will be too low, which will affect the productivity and practical value. However, this preferred condition is obtained by experimenting with a small experimental furnace with a volume of 5L, which may not be applicable to other reactors whose volume is too different from it. Therefore, the present application does not limit the flow rate of the reaction gas to the above-mentioned preferred range, and it can be adjusted adaptively according to the preparation conditions.

作为本申请可选的技术方案，所述反应的方式为化学气相沉积，所述化学气相沉积的反应温度为700℃～1450℃，例如700℃、800℃、900℃、1000℃、1050℃、1100℃、1150℃、1200℃、1250℃、1300℃、1350℃、1400℃或1450℃等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。反应温度低于700℃，影响原位生长出含石墨烯结构的碳包覆层，会导致无法在产品的拉曼测试中观测到石墨烯结构特性峰D。As an optional technical solution of the present application, the method of the reaction is chemical vapor deposition, and the reaction temperature of the chemical vapor deposition is 700°C to 1450°C, for example, 700°C, 800°C, 900°C, 1000°C, 1050°C, 1100°C, 1150°C, 1200°C, 1250°C, 1300°C, 1350°C, 1400°C or 1450°C, etc., but are not limited to the listed values, and other unlisted values within this range of values are equally applicable. The reaction temperature is lower than 700°C, which affects the in-situ growth of the carbon coating layer containing the graphene structure, which will cause the graphene structure characteristic peak D to be unable to be observed in the Raman test of the product.

在其中一些实施例中，所述化学气相沉积的反应温度为700℃～1150℃，例如700℃、800℃、900℃、1000℃、1050℃或1150℃等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。本申请中，如果反应温度过高，会导致碳包覆层与含硅内核发生反应生成电化学惰性的碳化硅，使产品电化学性能劣化；如果反应温度过低，会导致石墨烯结构无法生成。In some of the embodiments, the reaction temperature of the chemical vapor deposition is 700°C to 1150°C, such as 700°C, 800°C, 900°C, 1000°C, 1050°C, or 1150°C, but is not limited to the listed values. , Other unlisted values within this value range also apply. In this application, if the reaction temperature is too high, it will cause the carbon coating layer to react with the silicon-containing core to produce electrochemically inert silicon carbide, which will degrade the electrochemical performance of the product; if the reaction temperature is too low, the graphene structure will not be formed. .

在其中一些实施例中，所述化学气相沉积的保温时间为3h～16h，例如3h、4h、5h、6h、7h、8h、9h、10h、11h、12h、13h、14h、15h或16h等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。In some embodiments, the holding time of the chemical vapor deposition is 3h-16h, for example, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h or 16h, etc., However, it is not limited to the listed values, and other unlisted values within this range of values are also applicable.

在其中一些实施例中，所述化学气相沉积的反应气压为1.0atm～10.0atm，例如1.0atm、2.0atm、4.0atm、6.0atm、7.0atm、8.0atm、9.0atm或10.0atm等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。本申请中，如果反应气压过高，会导致反应速率过慢，影响生产性和实用性，同时存在安全风险；如果反应气压过低，会导致无法确保反应环境的惰性气氛，如果压力低于于1atm，甚至可能会导致空气倒吸入有高温可燃气体的反应室，引发严重安全风险。In some of the embodiments, the reaction pressure of the chemical vapor deposition is 1.0atm-10.0atm, such as 1.0atm, 2.0atm, 4.0atm, 6.0atm, 7.0atm, 8.0atm, 9.0atm or 10.0atm, etc., but not It is not limited to the listed values, and other unlisted values within this range of values are also applicable. In this application, if the reaction pressure is too high, the reaction rate will be too slow, affecting productivity and practicability, and there is a safety risk; if the reaction pressure is too low, it will lead to an inert atmosphere that cannot ensure the reaction environment. If the pressure is lower than 1atm, it may even cause air to be sucked into the reaction chamber with high-temperature combustible gas, causing serious safety risks.

本申请中，采用上述反应气体流速、反应温度、反应气压以及保温时间可以使这些操作条件相互配合，更好地提升产品的性能，并确保代表石墨烯结构的特征峰D的出现。In this application, the use of the above-mentioned reaction gas flow rate, reaction temperature, reaction pressure, and holding time can make these operating conditions coordinate with each other, better improve the performance of the product, and ensure the appearance of the characteristic peak D representing the graphene structure.

在其中一些实施例中，如图1所示，所述方法包括以下步骤S100～S200：In some of the embodiments, as shown in FIG. 1, the method includes the following steps S100-S200:

S100、在保护性气氛下，将含硅颗粒加热至700℃～1450℃；S100. Heat the silicon-containing particles to 700°C to 1450°C in a protective atmosphere;

S200、通入反应气体进行化学气相沉积，所述反应气体包括含碳气体，使得含硅颗粒的至少部分表面形成碳包覆层，得到复合负极材料。In S200, a reaction gas is introduced to perform chemical vapor deposition, and the reaction gas includes a carbon-containing gas, so that at least a part of the surface of the silicon-containing particles forms a carbon coating layer to obtain a composite negative electrode material.

作为本申请优选的技术方案，所述反应在化学气相沉积(CVD)装置中进行。As a preferred technical solution of the present application, the reaction is carried out in a chemical vapor deposition (CVD) device.

在其中一些实施例中，所述化学气相沉积装置包括如回转式化学气相沉积(CVD) 反应炉、等离子增强化学气相沉积(CVD)反应炉、化学气相沉积(CVD)管式炉或流化床中的任意一种或至少两种的组合。In some of the embodiments, the chemical vapor deposition apparatus includes, for example, a rotary chemical vapor deposition (CVD) reactor, a plasma enhanced chemical vapor deposition (CVD) reactor, a chemical vapor deposition (CVD) tube furnace, or a fluidized bed Any one or a combination of at least two of them.

作为本申请可选的技术方案，所述碳包覆层为无机碳材料层。需要说明的是，碳包覆层包覆在含硅颗粒的表面，本申请中所指的表面不仅仅是颗粒的平整表面，碳包覆层还可以填充于颗粒表面的裂缝、孔道等结构内，在此不做限定。As an optional technical solution of the present application, the carbon coating layer is an inorganic carbon material layer. It should be noted that the carbon coating layer covers the surface of the silicon-containing particles. The surface referred to in this application is not only the flat surface of the particles. The carbon coating layer can also be filled in the cracks, pores and other structures on the surface of the particles. , It is not limited here.

在其中一些实施例中，在所述复合负极材料中，碳包覆层的质量分数为1％～65％，例如1％、10％、20％、30％、40％、50％、60％或65％等，但并不仅限于所列举的数值，该数值范围内其他未列举的数值同样适用。本申请中，碳包覆层的质量分数低于1％会导致包覆量不足，无法充分发挥该产品性能，碳包覆层的质量分数高于65％会导致碳包覆量过高，影响容量的同时阻碍锂离子传输，降低负极材料的综合性能。In some of the embodiments, in the composite negative electrode material, the mass fraction of the carbon coating layer is 1%-65%, for example, 1%, 10%, 20%, 30%, 40%, 50%, 60% Or 65%, etc., but not limited to the listed values, and other unlisted values within this range of values are also applicable. In this application, if the mass fraction of the carbon coating layer is less than 1%, the coating amount will be insufficient, and the product performance cannot be fully utilized. The mass fraction of the carbon coating layer higher than 65% will cause the carbon coating amount to be too high and affect At the same time, the capacity hinders lithium ion transmission and reduces the overall performance of the negative electrode material.

在其中一些实施例中，所述制备方法还包括：化学气相沉积反应后自然冷却。In some of the embodiments, the preparation method further includes: natural cooling after the chemical vapor deposition reaction.

作为本申请所述制备方法的进一步可选技术方案，所述方法包括以下步骤：As a further optional technical solution of the preparation method described in this application, the method includes the following steps:

第三方面，本申请提供一种锂离子电池，所述锂离子电池包含上述第一方面所述的复合负极材料或上述第二方面所述的制备方法制得的复合负极材料。In a third aspect, the present application provides a lithium ion battery, the lithium ion battery comprising the composite negative electrode material described in the first aspect or the composite negative electrode material produced by the preparation method described in the second aspect.

下面分多个实施例对本发明实施例进行进一步的说明。其中，本发明实施例不限定于以下的具体实施例。在保护范围内，可以适当的进行变更实施。The following further describes the embodiments of the present invention in multiple embodiments. Among them, the embodiments of the present invention are not limited to the following specific embodiments. Within the scope of protection, changes can be appropriately implemented.

实施例1Example 1

本实施例按照如下方法制备复合负极材料：In this embodiment, the composite negative electrode material was prepared according to the following method:

取SiO粉末1.5kg，加入到5L实验型间歇式回转CVD炉中，向炉内通入氮气进行气氛置换，待排出气体中氧含量低于200ppm后，在持续通入氮气的情况下开始升温，升温至900℃后，以氮气为载气通入0.8L/min的甲烷，保持反应气压为1.2atm，持续反应6h后，切断甲烷气体，开始自然降温，得到所述复合负极材料。Take 1.5 kg of SiO powder and add it to a 5L experimental batch rotary CVD furnace, and pass nitrogen into the furnace for atmosphere replacement. After the oxygen content in the exhaust gas is less than 200ppm, start to heat up while continuing to pass nitrogen. After the temperature was raised to 900°C, 0.8 L/min of methane was introduced using nitrogen as a carrier gas, and the reaction pressure was maintained at 1.2 atm. After the reaction was continued for 6 hours, the methane gas was cut off and the temperature began to cool naturally to obtain the composite negative electrode material.

将所述负极材料出料后打散过筛，进行拉曼光谱测试(采用日本HORIBA的XPLORA型激光共焦拉曼光谱仪，使用激光波长532nm，测试范围100cm ^-1至2800cm ^-1，其他实施例和对比例均采用该型号的拉曼光谱仪进行测试，测试条件也与实施例1相同)和碳含量测试(采用德国布鲁克的G4 ICARUS HF型红外硫碳分析仪进行测试，其他实施例和对比例均采用该型号的测试仪测试碳含量)。 After discharging the negative electrode material, it is broken and sieved, and the Raman spectroscopy test is carried out (using Japan HORIBA XPLORA laser confocal Raman spectrometer, using laser wavelength 532nm, test range 100cm ^-1 to 2800cm ^-1 , other embodiments The Raman spectrometer of this model and the comparative example were used for testing, and the test conditions were the same as in Example 1) and carbon content test (using the G4 ICARUS HF infrared sulfur carbon analyzer of Germany Bruker for testing, other examples and comparative examples This type of tester is used to test the carbon content).

本实施例制备的负极材料包括SiO内核和包覆在SiO内核表面的无机碳材料包覆层，碳包覆层的质量分数为2.53％。本实施例制备的负极材料的拉曼光谱中的硅特征峰A在504cm ^-1处，碳特征峰B在1352cm ^-1处，碳特征峰C在1601cm ^-1处，石墨烯结构特征峰D在2695cm ^-1处，峰强度I _A＝90.2，I _B＝109.0，I _D＝54.5，I _A/I _D为1.65，I _D/I _B为0.50。 The negative electrode material prepared in this embodiment includes a SiO core and an inorganic carbon material coating layer covering the surface of the SiO core, and the mass fraction of the carbon coating layer is 2.53%. In the Raman spectrum of the negative electrode material prepared in this example, the silicon characteristic peak A is at 504 cm ^-1 , the carbon characteristic peak B is at 1352 cm ^-1 , the carbon characteristic peak C is at 1601 cm ^-1 , and the graphene structure characteristic peak D is at ^-1 2695cm, peak intensity _{_{I A = 90.2, I B =}} 109.0, I D = 54.5, I A / I D of 1.65, I _D / I _B is 0.50.

本实施例制备的复合负极材料的性能测试结果见表1。The performance test results of the composite negative electrode material prepared in this example are shown in Table 1.

图2为本实施例制备的复合负极材料的拉曼光谱，由该图可以看出产品出现石墨烯结构的特征峰。Figure 2 is the Raman spectrum of the composite negative electrode material prepared in this embodiment. From the figure, it can be seen that the product has characteristic peaks of the graphene structure.

图3为本实施例制备的复合负极材料的循环性能曲线，由该图可以看出产品具有较好的循环性能，且倍率性能(1C/0.1C)较好。Figure 3 is the cycle performance curve of the composite negative electrode material prepared in this example. It can be seen from the figure that the product has better cycle performance and better rate performance (1C/0.1C).

实施例2Example 2

取多孔硅粉末150g(比表面积>150cm ²/g)，加入到5L实验型间歇式回转CVD炉中，向炉内通入氮气进行气氛置换，待排出气体中氧含量低于200ppm后，在持续通入氮气的情况下开始升温，升温至935℃后，以氮气为载气通入1.0L/min的甲烷，保持反应气压为2.0atm，持续反应10h后，切断甲烷气体，开始自然降温，得到所述复合负极材料。 Take 150g of porous silicon powder (specific surface area>150cm ² /g) and add it to a 5L experimental batch rotary CVD furnace, and pass nitrogen into the furnace for atmosphere replacement. After the oxygen content in the exhaust gas is less than 200ppm, continue When nitrogen is introduced, the temperature is increased. After the temperature is increased to 935°C, 1.0L/min of methane is introduced using nitrogen as the carrier gas, and the reaction pressure is maintained at 2.0atm. After the reaction continues for 10 hours, the methane gas is cut off and the temperature begins to cool down naturally. The composite negative electrode material.

将所述负极材料出料后打散过筛，进行测试。After discharging the negative electrode material, it is scattered and screened for testing.

本实施例制备的负极材料包括多孔硅内核和包覆在多孔硅内核表面的无机碳材料包覆层，碳包覆层的质量分数为41.2％。本实施例制备的负极材料的拉曼光谱中的硅特征峰A在501cm ^-1处，碳特征峰B在1348cm ^-1处，碳特征峰C在1591cm ^-1处，石墨烯结构特征峰D在2682cm ^-1处，峰强度I _A/I _D为4.35，I _D/I _B为0.34。 The negative electrode material prepared in this embodiment includes a porous silicon core and an inorganic carbon material coating layer covering the surface of the porous silicon core, and the mass fraction of the carbon coating layer is 41.2%. In the Raman spectrum of the negative electrode material prepared in this example, the silicon characteristic peak A is at 501 cm ^-1 , the carbon characteristic peak B is at 1348 cm ^-1 , the carbon characteristic peak C is at 1591 cm ^-1 , and the graphene structure characteristic peak D is at At 2682 cm ^-1 , the peak intensity I _A /I _D is 4.35, and I _D /I _B is 0.34.

图4为本实施例制备的复合负极材料的拉曼光谱，由该图可以看出产品出现石墨烯结构特征峰。Figure 4 is the Raman spectrum of the composite negative electrode material prepared in this embodiment. From this figure, it can be seen that the product has characteristic peaks of graphene structure.

图5为本实施例制备的复合负极材料的循环性能曲线，由该图可以看出产品具有较好的循环性能，且倍率性能(1C/0.1C)较好。Figure 5 is the cycle performance curve of the composite negative electrode material prepared in this example. It can be seen from the figure that the product has better cycle performance and better rate performance (1C/0.1C).

实施例3Example 3

取SiO粉末1.5kg，加入到5L实验型间歇式回转CVD炉中，向炉内通入氮气进行气氛置换，待排出气体中氧含量低于200ppm后，在持续通入氮气的情况下开始升温，升温至700℃后，以氮气为载气通入1.8L/min的乙炔和氢气的混合气(乙炔与氢气的摩尔比为2:1)，保持反应气压为1.0atm，持续反应16h后，切断混合气，开始自然降温，得到所述复合负极材料。Take 1.5 kg of SiO powder and add it to a 5L experimental batch rotary CVD furnace, and pass nitrogen into the furnace for atmosphere replacement. After the oxygen content in the exhaust gas is less than 200ppm, start to heat up while continuing to pass nitrogen. After heating to 700°C, a 1.8L/min mixture of acetylene and hydrogen (the molar ratio of acetylene to hydrogen is 2:1) was introduced using nitrogen as the carrier gas, and the reaction pressure was maintained at 1.0 atm. After the reaction continued for 16 hours, the system was switched off. The mixed gas starts to cool down naturally to obtain the composite negative electrode material.

本实施例制备的负极材料包括SiO内核和包覆在SiO内核表面的无机碳材料包覆层，碳包覆层的质量分数为4.3％。本实施例制备的负极材料的拉曼光谱中的硅特征峰A在503cm ^-1处，碳特征峰B在1351cm ^-1处，碳特征峰C在1597cm ^-1处，石墨烯结构特征峰D在2691cm ^-1处，峰强度I _A/I _D为6.73，I _D/I _B为0.34。 The negative electrode material prepared in this embodiment includes a SiO core and an inorganic carbon material coating layer covering the surface of the SiO core, and the mass fraction of the carbon coating layer is 4.3%. Raman spectrum of the negative electrode material prepared in the present embodiment the silicon characteristic peaks at 503cm ^-1 A, the carbon B characteristic peaks at 1351cm ^-1, the carbon peaks at 1597cm ^-1 in the C, D graphene structure characteristic peaks At 2691 cm ^-1 , the peak intensity I _A /I _D is 6.73, and I _D /I _B is 0.34.

实施例4Example 4

取Si-O-C-Li复合物2kg，加入到5L实验型间歇式回转CVD炉中，向炉内通入氩气进行气氛置换，待排出气体中氧含量低于200ppm后，在持续通入氮气的情况下开始升温，升温至1150℃后，以氩气为载气通入0.8L/min的乙炔和氢气的混合气(乙炔与氢气的摩尔比为4:1)，保持反应气压为10.0atm，持续反应3h后，切断混合气，开始自然降温，得到所述复合负极材料。Take 2kg of Si-OC-Li composite and add it to a 5L experimental batch rotary CVD furnace, and then pass argon into the furnace for atmosphere replacement. After the oxygen content in the exhaust gas is less than 200ppm, continue to pass nitrogen Under the circumstances, the temperature began to rise. After the temperature was raised to 1150°C, 0.8L/min of acetylene and hydrogen mixed gas (the molar ratio of acetylene to hydrogen was 4:1) was introduced with argon as the carrier gas, and the reaction pressure was maintained at 10.0atm. After continuing the reaction for 3 hours, the mixed gas is cut off and the temperature starts to cool naturally to obtain the composite negative electrode material.

本实施例制备的复合负极材料包括氧化亚硅/硅/偏硅酸锂内核和包覆在氧化亚硅/硅/偏硅酸锂内核表面的无机碳材料包覆层，碳包覆层的质量分数为2.5％。本实施例制备的负极材料的拉曼光谱中的硅特征峰A在501cm ^-1处，碳特征峰B在1347cm ^-1处，碳特征峰C在1598cm ^-1处，石墨烯结构特征峰D在2692cm ^-1处，峰强度I _A/I _D为8.59，I _D/I _B为0.24。 The composite negative electrode material prepared in this embodiment includes a silicon oxide/silicon/lithium metasilicate core and an inorganic carbon material coating layer covering the surface of the silicon oxide/silicon/lithium metasilicate core. The quality of the carbon coating layer The score is 2.5%. In the Raman spectrum of the negative electrode material prepared in this example, the silicon characteristic peak A is at 501 cm ^-1 , the carbon characteristic peak B is at 1347 cm ^-1 , the carbon characteristic peak C is at 1598 cm ^-1 , and the graphene structure characteristic peak D is at At 2692 cm ^-1 , the peak intensity I _A /I _D is 8.59, and I _D /I _B is 0.24.

实施例5Example 5

本实施例除了乙炔与氢气的摩尔比为10:1之外，其他操作条件和原料种类均与实施例3相同。In this embodiment, except that the molar ratio of acetylene to hydrogen is 10:1, other operating conditions and types of raw materials are the same as those in Example 3.

本实施例制备的负极材料包括SiO内核和包覆在SiO内核表面的无机碳材料包覆层，碳包覆层的质量分数为4.1％。本实施例制备的负极材料的拉曼光谱中的硅特征峰A在501cm ^-1处，碳特征峰B在1347cm ^-1处，碳特征峰C在1592cm ^-1处，石墨烯结构特征峰D在2685cm ^-1处，峰强度I _A/I _D为6.68，I _D/I _B为0.30。 The negative electrode material prepared in this embodiment includes a SiO core and an inorganic carbon material coating layer covering the surface of the SiO core, and the mass fraction of the carbon coating layer is 4.1%. In the Raman spectrum of the negative electrode material prepared in this example, the silicon characteristic peak A is at 501 cm ^-1 , the carbon characteristic peak B is at 1347 cm ^-1 , the carbon characteristic peak C is at 1592 cm ^-1 , and the graphene structure characteristic peak D is at At 2685 cm ^-1 , the peak intensity I _A /I _D is 6.68, and I _D /I _B is 0.30.

实施例6Example 6

本实施例除了反应气压为13atm之外，其他原料和操作条件均与实施例1相同。In this embodiment, except that the reaction pressure is 13 atm, other raw materials and operating conditions are the same as those in Embodiment 1.

本实施例制备的负极材料包括SiO内核和包覆在SiO内核表面的无机碳材料包覆层，碳包覆层的质量分数为0.7％。本实施例制备的负极材料的拉曼光谱中的硅特征峰A在505cm ^-1处，碳特征峰B在1352cm ^-1处，碳特征峰C在1597cm ^-1处，石墨烯结构特征峰D在2701cm ^-1处，峰强度I _A/I _D为19.2，I _D/I _B为0.61。 The negative electrode material prepared in this embodiment includes a SiO core and an inorganic carbon material coating layer covering the surface of the SiO core, and the mass fraction of the carbon coating layer is 0.7%. In the Raman spectrum of the negative electrode material prepared in this example, the silicon characteristic peak A is at 505 cm ^-1 , the carbon characteristic peak B is at 1352 cm ^-1 , the carbon characteristic peak C is at 1597 cm ^-1 , and the graphene structure characteristic peak D is at At 2701 cm ^-1 , the peak intensity I _A /I _D is 19.2, and I _D /I _B is 0.61.

实施例7Example 7

本实施例除了反应温度为1450℃之外，其他原料和操作条件均与实施例1相同。In this embodiment, except that the reaction temperature is 1450° C., other raw materials and operating conditions are the same as those in Embodiment 1.

本实施例制备的负极材料包括SiO内核和包覆在SiO内核表面的无机碳材料包覆层，碳包覆层的质量分数为4.3％。本实施例制备的负极材料的拉曼光谱中的硅特征峰A在502cm ^-1处，碳特征峰B在1342cm ^-1处，碳特征峰C在1601cm ^-1处，石墨烯结构特征峰D在2694cm ^-1处，峰强度I _A/I _D为5.4，I _D/I _B为0.24。 The negative electrode material prepared in this embodiment includes a SiO core and an inorganic carbon material coating layer covering the surface of the SiO core, and the mass fraction of the carbon coating layer is 4.3%. In the Raman spectrum of the anode material prepared in this example, the silicon characteristic peak A is at 502 cm ^-1 , the carbon characteristic peak B is at 1342 cm ^-1 , the carbon characteristic peak C is at 1601 cm ^-1 , and the graphene structure characteristic peak D is at At 2694 cm ^-1 , the peak intensity I _A /I _D is 5.4, and I _D /I _B is 0.24.

实施例8Example 8

本实施例除了不通入氢气而仅仅通入乙炔，且反应气体通入速度为0.1L/min，持续反应24h之外，其他原料和操作条件均与实施例3相同。In this embodiment, except that hydrogen is not fed but only acetylene is fed, and the reaction gas feeding rate is 0.1 L/min, and the reaction continues for 24 hours, other raw materials and operating conditions are the same as those of Example 3.

本实施例制备的负极材料包括SiO内核和包覆在SiO内核表面的无机碳材料包覆层，碳包覆层的质量分数为6.4％。本实施例制备的负极材料的拉曼光谱中的硅特征峰A在503cm ^-1处，碳特征峰B在1341cm ^-1处，碳特征峰C在1602cm ^-1处，石墨烯结构特征峰D在2696cm ^-1处，峰强度I _A/I _D为4.5，I _D/I _B为0.16。 The negative electrode material prepared in this embodiment includes a SiO core and an inorganic carbon material coating layer covering the surface of the SiO core, and the mass fraction of the carbon coating layer is 6.4%. Raman spectrum of the negative electrode material prepared in the present embodiment the silicon characteristic peaks at 503cm ^-1 A, the carbon B characteristic peaks at 1341cm ^-1, the carbon peaks at 1602cm ^-1 in the C, D graphene structure characteristic peaks At 2696 cm ^-1 , the peak intensity I _A /I _D is 4.5, and I _D /I _B is 0.16.

对比例1Comparative example 1

本对比例按照如下方法制备负极材料：In this comparative example, the negative electrode material was prepared according to the following method:

取SiO粉末1.5kg，加入到实验型间歇式回转CVD炉中，向炉内通入氮气进行气氛置换，待排出气体中氧含量低于200ppm后，在持续通入氮气的情况下开始升温，升温至680℃后，以氮气为载气通入1.5L/min的乙炔，保持反应气压为1.4atm，持续反应5h后，切断乙炔气体，开始自然降温，得到负极材料。Take 1.5 kg of SiO powder and add it to the experimental batch rotary CVD furnace, and pass nitrogen into the furnace for atmosphere replacement. After the oxygen content in the exhaust gas is less than 200ppm, start to heat up while continuing to pass nitrogen. After reaching 680°C, 1.5L/min of acetylene was introduced using nitrogen as a carrier gas, and the reaction pressure was maintained at 1.4atm. After the reaction was continued for 5 hours, the acetylene gas was cut off and the temperature began to cool naturally to obtain a negative electrode material.

该负极材料的碳包覆层的质量分数为4.21％(即碳含量)，拉曼测试结果未观察到石墨烯结构特征峰D。The mass fraction of the carbon coating layer of the negative electrode material is 4.21% (that is, the carbon content), and the characteristic peak D of the graphene structure is not observed in the Raman test result.

本对比例制备的负极材料的性能测试结果见表1。The performance test results of the negative electrode material prepared in this comparative example are shown in Table 1.

图5为本对比例制备的复合负极材料的拉曼光谱，由该图可以看出产品无石墨烯结构。Figure 5 is the Raman spectrum of the composite negative electrode material prepared in the comparative example. It can be seen from the figure that the product has no graphene structure.

图6为本对比例制备的复合负极材料的循环性能曲线，由该图可以看出产品循环性能和倍率性能均出现劣化。Figure 6 is the cycle performance curve of the composite negative electrode material prepared in the comparative example. It can be seen from the figure that both the cycle performance and rate performance of the product have deteriorated.

对比例2Comparative example 2

本对比例除了反应温度为500℃之外，其他原料和操作条件均与实施例1相同。In this comparative example, except that the reaction temperature is 500° C., other raw materials and operating conditions are the same as in Example 1.

本对比例得到的负极材料经拉曼测试，结果未观察到石墨烯结构特征峰D。The negative electrode material obtained in this comparative example was subjected to a Raman test, and as a result, the characteristic peak D of the graphene structure was not observed.

性能测试方法Performance test method

将各实施例和对比例制备的负极材料与商业石墨负极以10:90的比例进行混合作为负极活性物质，选用石墨为深圳市贝特瑞新能源材料股份有限公司生产的人造石墨S360系列，电极片涂层中活性物质、导电剂(Super P)和粘结剂 (CMC+SBR)的质量比为92:4:4，对电极为锂片；使用1mol/L的LiPF ₆/EC+DMC+EMC(v/v＝1:1:1)电解液、Celgard2400隔膜组装扣式电池。用该种电池进行循环测试。 The negative electrode material prepared in each example and comparative example was mixed with a commercial graphite negative electrode in a ratio of 10:90 as the negative electrode active material, and the graphite was selected as the artificial graphite S360 series produced by Shenzhen Beterui New Energy Materials Co., Ltd. The mass ratio of active material, conductive agent (Super P) and binder (CMC+SBR) in the sheet coating is 92:4:4, and the counter electrode is a lithium sheet; 1mol/L LiPF ₆ /EC+DMC+ is used EMC (v/v=1:1:1) electrolyte, Celgard2400 diaphragm assembly button cell. Use this kind of battery for cycle test.

各实施例和对比例制备的负极材料作为负极活性物质，电极片涂层中活性物质、导电剂(Super P)和粘结剂(CMC+SBR)的质量比为92:4:4，对电极为锂片；使用1mol/L的LiPF ₆/EC+DMC+EMC(v/v＝1:1:1)电解液、Celgard2400隔膜组装扣式电池。用该种电池进行首圈充放电测试。 The negative electrode material prepared in each example and comparative example is used as the negative electrode active material. The mass ratio of the active material, the conductive agent (Super P) and the binder (CMC+SBR) in the electrode sheet coating is 92:4:4, and the counter electrode Lithium sheet; 1mol/L LiPF ₆ /EC+DMC+EMC (v/v=1:1:1) electrolyte and Celgard2400 diaphragm are used to assemble the button cell. Use this kind of battery for the first round of charge and discharge test.

将各实施例和对比例制备的负极材料与商业石墨负极以10：90的比例进行混合作为负极活性物质，选用石墨为深圳市贝特瑞新能源材料股份有限公司生产的人造石墨S360系列，负极电极片涂层中负极活性物质、导电剂(Super P)和粘结剂(CMC+SBR)的质量比为95.8:1.0:3.2，正极电极片涂层中正极活性物质(NCA三元材料，深圳市贝特瑞新能源材料股份有限公司生产，产品名称：N8-S)、导电剂(Super P)、粘结剂(PVDF)的质量比为97.3：1.0：1.7，使用隔膜为Celgard2400隔膜、使用1mol/L的LiPF ₆/EC+DMC+EMC(v/v＝1:1:1)电解液，装配18650型电池，用于高温老化损失测试。 The negative electrode material prepared in each example and comparative example was mixed with a commercial graphite negative electrode in a ratio of 10:90 as the negative electrode active material, and the graphite was selected as the artificial graphite S360 series produced by Shenzhen Beterui New Energy Materials Co., Ltd., the negative electrode The mass ratio of the negative active material, the conductive agent (Super P) and the binder (CMC+SBR) in the electrode sheet coating is 95.8:1.0:3.2, and the positive electrode active material (NCA ternary material, Shenzhen Produced by Beiterui New Energy Materials Co., Ltd., product name: N8-S), conductive agent (Super P), and binder (PVDF) with a mass ratio of 97.3:1.0:1.7. The diaphragm used is Celgard2400 diaphragm. 1mol/L LiPF ₆ /EC+DMC+EMC (v/v=1:1:1) electrolyte, equipped with 18650 battery, used for high temperature aging loss test.

采用蓝电电池测试***对上述电池进行电化学测试。The blue battery test system is used to conduct electrochemical tests on the above-mentioned batteries.

在常温下，扣式电池以0.1C、0.2C、0.5C各循环一周，后以1C充放电循环47周，以第50周的容量除以第1周容量，得产品50周循环容量保持率，0.1C容量除以1C容量用于评估产品倍率性能。At room temperature, the button cell is cycled at 0.1C, 0.2C, and 0.5C for one week, and then charged and discharged at 1C for 47 weeks, and the capacity of the 50th week is divided by the capacity of the first week to obtain the 50-week cycle capacity retention rate of the product. , 0.1C capacity divided by 1C capacity is used to evaluate product rate performance.

将18650电池经过化成后，使用0.3C在2.5～4.2V电压区间进行充放电记录可逆容量后，再0.3C充电至4.2V，以满电状态在60℃温度静置3天，3天后以0.3C放电至2.5V以存放后可放出的容量和记录的可逆容量计算差值，计算的差值除以记录的可逆容量即为产品的老化损失。After forming the 18650 battery, use 0.3C to charge and discharge the reversible capacity in the voltage range of 2.5~4.2V, and then charge it to 4.2V at 0.3C, and let it stand at 60℃ for 3 days in a fully charged state. After 3 days, the rate will be 0.3 C is discharged to 2.5V to calculate the difference between the discharged capacity after storage and the recorded reversible capacity. The calculated difference divided by the recorded reversible capacity is the aging loss of the product.

上述性能测试的结果见表1.The results of the above performance test are shown in Table 1.

表1Table 1

综合上述实施例和对比例可知，本申请实施例1～5制备的复合负极材料具有独特的拉曼光谱峰，特征峰D为石墨烯结构特征峰，且I _A/I _D和I _D/I _B较优，使得上述实施例提供的复合负极材料具有循环容量保持率高、倍率性能好、高温老化损失小等优点。 The above embodiments and Comparative Examples above, the present application the composite negative electrode material prepared in Examples 1 to 5 embodiment has a unique Raman spectrum peak, peak D is a characteristic peaks graphene structure, and I _A / I _D and I _D / I _{B is} better, so that the composite negative electrode material provided by the foregoing embodiment has the advantages of high cycle capacity retention, good rate performance, and low high-temperature aging loss.

实施例6的反应气压过高，导致反应速率过低，碳含量较低，而实施例1的反应气压为1.2atm，根据实施例1的复合负极材料制成的电池的容量保持率、循环保持率及老化损失等各项性能均优于实施例6，由此可见，反应气压控制在1.0atm～10.0atm范围较为合适，既可以保障产品的性能，又能降低生产安全风险。The reaction pressure of Example 6 is too high, resulting in too low reaction rate and low carbon content. However, the reaction pressure of Example 1 is 1.2 atm. The capacity retention rate and cycle retention of the battery made of the composite anode material according to Example 1 are The performances such as rate and aging loss are better than those of Example 6. It can be seen that it is more appropriate to control the reaction pressure in the range of 1.0 atm to 10.0 atm, which can not only ensure the performance of the product, but also reduce production safety risks.

实施例7的反应温度过高达到边界值，导致少量碳包覆层与含硅颗粒反应，生成少量电化学惰性的碳化硅，而实施例1的反应温度为900℃，反应较为温和，根据实施例1的复合负极材料制成的电池的首圈可逆比容量、容量保持率、循环保持率及老化损失等各项性能均优于实施例7，由此可见，反应温度控制在700℃～1150℃范围较为合适，可以保障产品的电化学容量和倍率性能。The reaction temperature of Example 7 is too high to the boundary value, which causes a small amount of carbon coating layer to react with silicon-containing particles to produce a small amount of electrochemically inert silicon carbide. However, the reaction temperature of Example 1 is 900°C, and the reaction is relatively mild. The first-turn reversible specific capacity, capacity retention rate, cycle retention rate and aging loss of the battery made of the composite negative electrode material of Example 1 are better than those of Example 7. It can be seen that the reaction temperature is controlled at 700°C to 1150. The ℃ range is more suitable, which can guarantee the electrochemical capacity and rate performance of the product.

实施例8中未使用辅助气体氢气，相比于实施例3，实施例8需要使用较低的乙炔流量才能产生石墨烯结构，这使得实施例8所需的反应时间更长，生产效率降低，由此可见，加入辅助气体可以控制乙炔气体的反应速度，提高石墨烯结构的生成效率。The auxiliary gas hydrogen is not used in Example 8. Compared with Example 3, Example 8 needs to use a lower acetylene flow rate to produce the graphene structure, which makes the reaction time required in Example 8 longer and lowers the production efficiency. It can be seen that the addition of auxiliary gas can control the reaction rate of acetylene gas and improve the efficiency of graphene structure generation.

对比例1将实施例1中的甲烷换为乙炔并且反应温度过低，导致石墨烯结构无法生成。In Comparative Example 1, the methane in Example 1 was replaced with acetylene and the reaction temperature was too low, resulting in the failure of the graphene structure to be generated.

对比例2的反应温度过低，导致石墨烯结构无法生成。The reaction temperature of Comparative Example 2 was too low, resulting in the failure of the graphene structure to be formed.

由于对比例1、2中的负极材料不具有石墨烯结构，其难以维持复合负极材料与电解液的固液界面的稳定性，虽然首圈可逆比容量与实施例1～8相近，但是电池在长期循环后，容量保持率、循环保持率均有所下降，恶化电池的老化损失。而含有石墨烯结构的碳包覆层可以提升复合负极材料颗粒表面与电解液的固液界面稳定，形成均一的SEI膜，使得由含石墨烯结构的复合负极材料制成的电池的首圈可逆比容量、容量保持率、循环保持率及老化损失等各项性能均较有所改进。申请人声明，本申请通过上述实施例来说明本申请的详细方法，但本申请并不局限于上述详细方法，即不意味着本申请必须依赖上述详细方法才能实施。所属技术领域的技术人员应该明了，对本申请的任何改进，对本申请产品各原料的等效替换及辅助成分的添加、具体方式的选择等，均落在本申请的保护范围和公开范围之内。Since the negative electrode materials in Comparative Examples 1 and 2 do not have a graphene structure, it is difficult to maintain the stability of the solid-liquid interface between the composite negative electrode material and the electrolyte. Although the first-lap reversible specific capacity is similar to that of Examples 1-8, the battery is After long-term cycling, the capacity retention rate and cycle retention rate both decrease, worsening the aging loss of the battery. The carbon coating layer containing the graphene structure can improve the stability of the solid-liquid interface between the surface of the composite negative electrode material particle and the electrolyte, forming a uniform SEI film, making the first circle of the battery made of the composite negative electrode material containing the graphene structure reversible Various properties such as specific capacity, capacity retention rate, cycle retention rate and aging loss have all been improved. The applicant declares that this application uses the above-mentioned embodiments to illustrate the detailed methods of this application, but this application is not limited to the above-mentioned detailed methods, which does not mean that this application must rely on the above-mentioned detailed methods to be implemented. Those skilled in the art should understand that any improvement to this application, the equivalent replacement of each raw material of the product of this application, the addition of auxiliary components, the selection of specific methods, etc., fall within the scope of protection and disclosure of this application.

Claims

一种复合负极材料，其特征在于，所述复合负极材料包括含硅颗粒和碳包覆层，所述碳包覆层包覆所述含硅颗粒的至少部分表面；A composite negative electrode material, characterized in that the composite negative electrode material comprises silicon-containing particles and a carbon coating layer, and the carbon coating layer covers at least part of the surface of the silicon-containing particles;

在拉曼光谱中，所述复合负极材料在450cm ^-1～550cm ^-1间具有硅特征峰A，在1300cm ^-1～1400cm ^-1间具有碳特征峰B，在1530cm ^-1～1630cm ^-1间有碳特征峰C，在2500cm ^-1～2750cm ^-1间具有石墨烯结构特征峰D。 In the Raman spectroscopy, the composite negative electrode material has a characteristic silicon peak A between ^{450 cm -1} and 550 cm ^-1 ^{, a characteristic carbon peak B between 1300 cm -1} and 1400 ^{cm -1,} and a characteristic peak B between 1530 cm ^-1 and 1630 cm ^-1 There is a characteristic peak C of carbon, and a characteristic peak D of the graphene structure between ^{2500 cm -1} and 2750 cm ^-1.
根据权利要求1所述复合负极材料，其特征在于，在拉曼光谱中，所述硅特征峰A的峰强度I _A与所述石墨烯结构特征峰D的峰强度I _D的比值I _A/I _D大于0.1且小于30，且所述石墨烯结构特征峰D的峰强度I _D与所述碳特征峰B的峰强度I _B的比值I _D/I _B大于0且小于1。 The composite negative electrode material according to claim 1, wherein in the Raman spectrum, the _{ratio of the peak intensity I A} _{of the characteristic peak A of silicon to the peak intensity I D} of the characteristic peak D of the graphene structure _{I A} / I _{D is} greater than 0.1 and less than 30, and the ratio I _D /I _B _{of the peak intensity I D} _{of the characteristic peak D of the graphene structure to the peak intensity I B} of the characteristic carbon peak B is greater than 0 and less than 1.
根据权利要求1或2所述复合负极材料，其特征在于，其满足以下条件a～f的至少一者：The composite negative electrode material according to claim 1 or 2, characterized in that it satisfies at least one of the following conditions a to f:

a.所述含硅颗粒包括Si、SiO _x和硅酸盐中的至少一种，其中，0<x<2； a. The silicon-containing particles include _{at least one of Si, SiO x} and silicate, wherein 0<x<2;

b.所述含硅颗粒的平均粒径为0.1um～20um；b. The average particle size of the silicon-containing particles is 0.1um to 20um;

c.所述含硅颗粒的比表面积大于150cm ²/g； c. The specific surface area of the silicon-containing particles is greater than 150 cm ² /g;

d.所述碳包覆层为无机碳材料层；d. The carbon coating layer is an inorganic carbon material layer;

e.所述碳包覆层的厚度为10nm～300nm；e. The thickness of the carbon coating layer is 10 nm to 300 nm;

f.在所述复合负极材料中，所述碳包覆层的质量分数为1％～65％。f. In the composite negative electrode material, the mass fraction of the carbon coating layer is 1% to 65%.
一种复合负极材料的制备方法，其特征在于，所述方法包括以下步骤：A method for preparing a composite negative electrode material, characterized in that the method includes the following steps:

在保护性气氛下，通入反应气体与含硅颗粒进行反应，反应温度为700℃～1450℃，所述反应气体包括含碳气体，使得所述含硅颗粒的至少部分表面形成碳包覆层，得到所述复合负极材料。In a protective atmosphere, a reaction gas is introduced to react with silicon-containing particles, and the reaction temperature is 700°C to 1450°C. The reaction gas includes a carbon-containing gas, so that at least part of the surface of the silicon-containing particles forms a carbon coating layer , To obtain the composite negative electrode material.
根据权利要求4所述的制备方法，其特征在于，其满足以下条件a～f的至少一者：The preparation method according to claim 4, characterized in that it satisfies at least one of the following conditions a to f:

a.所述含硅颗粒包括Si、SiO _x和硅酸盐中的至少一种，其中，0<x<2； a. The silicon-containing particles include _{at least one of Si, SiO x} and silicate, wherein 0<x<2;

b.所述含硅颗粒的平均粒径为0.1um～20um；b. The average particle size of the silicon-containing particles is 0.1um to 20um;

c.所述含硅颗粒的比表面积大于150cm ²/g； c. The specific surface area of the silicon-containing particles is greater than 150 cm ² /g;

d.所述碳包覆层为无机碳材料层；d. The carbon coating layer is an inorganic carbon material layer;

e.所述碳包覆层的厚度为10nm～300nm；e. The thickness of the carbon coating layer is 10 nm to 300 nm;

f.在所述复合负极材料中，所述碳包覆层的质量分数为1％～65％。f. In the composite negative electrode material, the mass fraction of the carbon coating layer is 1% to 65%.
根据权利要求4或5所述的制备方法，其特征在于，The preparation method according to claim 4 or 5, wherein:

在拉曼光谱中，所述复合负极材料在450cm ^-1～550cm ^-1间具有硅特征峰A，在1300cm ^-1～1400cm ^-1间具有碳特征峰B，在1530cm ^-1～1630cm ^-1间有碳特征峰C，在2500cm ^-1～2750cm ^-1间具有石墨烯结构特征峰D； In the Raman spectroscopy, the composite negative electrode material has a characteristic silicon peak A between ^{450 cm -1} and 550 cm ^-1 ^{, a characteristic carbon peak B between 1300 cm -1} and 1400 ^{cm -1,} and a characteristic peak B between 1530 cm ^-1 and 1630 cm ^-1 There is a carbon characteristic peak C, and a graphene structure characteristic peak D between ^{2500 cm -1} and 2750 cm ^-1;

所述硅特征峰A的峰强度I _A与所述石墨烯结构特征峰D的峰强度I _D的比值I _A/I _D大于0.1且小于30，且所述石墨烯结构特征峰D的峰强度I _D与所述碳特征峰B的峰强度I _B的比值I _D/I _B大于0且小于1。 The peak intensity ratio of silicon peak A I _A characteristic of the graphene structure characteristic peak D is a peak intensity I _A to I _D / I _D is greater than 0.1 and less than 30, the peak intensity and characteristic peak graphene structure of D I _{_D} I _D ratio of the peak intensity of the carbon content of the peak B I _B / I _B is greater than 0 and less than 1.
根据权利要求4～6任一项所述的制备方法，其特征在于，其满足以下条件a～b的至少一者：The preparation method according to any one of claims 4 to 6, characterized in that it satisfies at least one of the following conditions a to b:

a.所述保护性气氛包括氮气、氦气、氖气、氩气、氪气和氙气中的至少一种；a. The protective atmosphere includes at least one of nitrogen, helium, neon, argon, krypton and xenon;

b.所述含碳气体包括甲烷、乙炔、乙烯、丙炔、丙烯、甲苯蒸气、苯蒸气、丙酮蒸气和甲醛蒸气中的至少一种。b. The carbon-containing gas includes at least one of methane, acetylene, ethylene, propyne, propylene, toluene vapor, benzene vapor, acetone vapor, and formaldehyde vapor.
根据权利要求4～7任一项所述的制备方法，其特征在于，所述反应气体还包括辅助气体，所述辅助气体包括氢气。The preparation method according to any one of claims 4 to 7, wherein the reaction gas further includes an auxiliary gas, and the auxiliary gas includes hydrogen.
根据权利要求8所述的制备方法，其特征在于，所述含碳气体和所述辅助气体的摩尔比为(2～10)：1。The preparation method according to claim 8, wherein the molar ratio of the carbon-containing gas and the auxiliary gas is (2-10):1.
根据权利要求4～6任一项所述的制备方法，其特征在于，其满足以下条件a～d的至少一者：The preparation method according to any one of claims 4 to 6, characterized in that it satisfies at least one of the following conditions a to d:

a.所述反应的方式为化学气相沉积；a. The method of the reaction is chemical vapor deposition;

b.所述反应的方式为化学气相沉积，所述化学气相沉积的反应温度为700℃～1150℃；b. The method of the reaction is chemical vapor deposition, and the reaction temperature of the chemical vapor deposition is 700°C to 1150°C;

c.所述反应的方式为化学气相沉积，所述化学气相沉积的保温时间为3h～16h；c. The method of the reaction is chemical vapor deposition, and the holding time of the chemical vapor deposition is 3h-16h;

d.所述反应的方式为化学气相沉积，所述化学气相沉积的反应气压为1.0atm～10.0atm。d. The method of the reaction is chemical vapor deposition, and the reaction pressure of the chemical vapor deposition is 1.0 atm to 10.0 atm.
根据权利要求4～10任一项所述的制备方法，其特征在于，所述方法包括以下步骤：The preparation method according to any one of claims 4 to 10, wherein the method comprises the following steps:

在保护性气氛下，将含硅颗粒加热至700℃～1450℃；In a protective atmosphere, heat the silicon-containing particles to 700°C to 1450°C;

通入反应气体进行化学气相沉积，所述反应气体包括含碳气体，使得含硅颗粒的至少部分表面形成碳包覆层，得到复合负极材料。The chemical vapor deposition is carried out by introducing a reaction gas, the reaction gas including a carbon-containing gas, so that at least part of the surface of the silicon-containing particles forms a carbon coating layer to obtain a composite negative electrode material.
根据权利要求4～10任一项所述的制备方法，其特征在于，所述方法包括以下步骤：The preparation method according to any one of claims 4 to 10, wherein the method comprises the following steps:

在保护性气氛下，将含硅颗粒加热至700℃～1150℃；In a protective atmosphere, heat the silicon-containing particles to 700°C to 1150°C;

将含碳气体与氢气按照摩尔比为(2～10)：1通入所述含硅颗粒中进行化学气相沉积反应，控制反应气压1.0atm～10.0atm，保温3h～16h，使得所述含硅颗粒的至少部分表面形成碳包覆层，得到所述复合负极材料。The carbon-containing gas and hydrogen are introduced into the silicon-containing particles at a molar ratio of (2-10):1 to perform chemical vapor deposition reaction, the reaction pressure is controlled to be 1.0atm-10.0atm, and the temperature is maintained for 3h-16h, so that the silicon-containing A carbon coating layer is formed on at least part of the surface of the particles to obtain the composite negative electrode material.
一种锂离子电池，其特征在于，所述锂离子电池包含如权利要求1～3任一项所述的复合负极材料或根据权利要求4～12任一项所述的制备方法制得的复合负极材料。A lithium ion battery, characterized in that the lithium ion battery comprises the composite anode material according to any one of claims 1 to 3 or the composite prepared by the preparation method according to any one of claims 4-12 Anode material.